1. Field of the Invention
The present invention relates to a technique for adjusting screen brightness of a display unit and more particularly to adjusting the display brightness of a screen display
2. Description of the Related Art
The display brightness of a display unit of electronic devices (e.g., a personal computer, etc.) is often varied significantly according to the data that is to be displayed. For example, when displaying text and data entered and edited while using an application such as a word processor or spreadsheet software, the background of the image on the screen is often displayed using a bright color, such as white. As a result, the user often lowers the screen brightness so as to make it easy to read displayed data.
In other situations, images are often displayed in a plurality of colors on the screen, and the brightness of the screen is inherently less. As a result, the user increases the display brightness of the screen so as to make it easier to watch the displayed images.
More particularly, the use of a specific type of display may also affect the resulting display brightness, and hence the user's visibility of the images displayed. For instance, for an LCD (Liquid Crystal Display), the visibility is often low at a dark display. This is because the pixels of the liquid crystal do not emit light themselves, unlike a CRT display. Therefore, it is known that a user of an LCD display must often adjust the brightness to improve the user's visibility of the screen images.
Generally, the LCD is provided with a back-light so as to improve the visibility of the display. Even some of the conventional LCDs are enabled to adjust the brightness of the back-light. Certain of such battery-driven systems, such as lap-top personal computers, can change the brightness of the back-light feature automatically in addition to the manual adjustment when the power supply is switched between an AC power source and a battery so as to suppress the power consumption of the LCD.
However, these systems must be operated manually to adjust the brightness of the back-light so as to improve the display visibility.
In each of these situations, it is known that conventional display units have a function for manually changing the screen brightness. As a result, a user modifies the rightness while performing his own visual assessment of the appropriateness of the brightness. However, it is not known to modify the brightness of the screen automatically in relation to that which is displayed. It is known to be problematic where in order to improve the display brightness for a higher visibility, the user must initiate and visually adjust the screen brightness manually.